1. Field of the Invention
The present invention relates to cameras that utilize film cartridges.
2. Description of the Related Art
Advanced photo system (APS) cameras have become quite popular among photography enthusiasts. Such cameras allow users to enjoy many benefits over prior photographic systems. For example, aside from allowing multiple imaging formats, APS cameras allow users to easily load film cartridges without having to handle or manage film strips. To achieve such benefits, APS cameras typically include film cartridge assemblies that automate the loading and support of film cartridges and the advancement of film strips during film exposure and movement operations.
Although APS film cartridges are easier to load than conventional film cartridges, certain problems have been realized with regard to film strip safety. In particular, because of the tight spaces involved in the typical APS camera, there is little tolerance for improper movement of a film strip that might result when a camera is hit or bumped unexpectedly. Such little tolerance for film strip movement is exacerbated by the fact that film cartridges that maintain such film strips are allowed, and often designed to move within corresponding compartments. As such, when a film strip extends from a film cartridge, the film strip may be forced to move when the film cartridge moves. If the film cartridge is forced to move beyond a certain distance, the film strip may become damaged if it improperly contacts other camera structures such as film strip guide members and the like. The damage that can result from such improper film strip movement includes creases, rips, tears, and scratches.
To further illustrate the aforementioned problems, attention is directed to drawing FIGS. 1A and 1B which are attached hereto. Depicted in FIGS. 1A and 1B are views of a film cartridge compartment taken from backside of a typical bottom-load type APS camera. The camera utilizes a film strip F maintained by an APS type film cartridge 4. Film cartridge 4 is maintained within film cartridge compartment 3 which has been closed in accordance with a cartridge compartment cover 82. Cartridge compartment cover 82 allows access to film cartridge 4 from the bottom of the camera. In FIG. 1A, the camera can be said to be in a "normal" state in that it has not yet been acted upon by a jarring force such as one resulting from an unexpected movement.
In film cartridge compartment 3, film cartridge 4 is supported by an upper spindle 11 which cooperatively engages with an upper end of a film windup shaft 41 (hereinafter "shaft 41") which is axially disposed within and accessible from the ends of film cartridge 4. A lower spindle 9 supports a lower end portion of shaft 41. Additionally, lower spindle 9 urges shaft 41 upward and toward upper spindle member 11 (i.e., in the direction specified as E1--the direction corresponding to the width of film strip F) in accordance with a spring 10.
During normal operation, a gap or space having dimension d1 is present between a bottom portion Fu of film strip F and a film guide rail 25. Another gap or space having dimension d2 is also present between a base plate 7 and the bottom portion of lower spindle 9 which results from spring 10 urging lower spindle 9 toward upper spindle 11. Normally, dimension d2 is larger than dimension d1. As such, the difference between the relative dimensions d1 and d2 has resulted in a serious problem with regard to film strip safety which is illustrated in FIG. 1B.
In FIG. 1B, the camera has been acted upon by a force such as one resulting from an impact that occurred during transport. As such, film cartridge 4 was caused to move in a downward direction (identified as direction E2). The impact to the camera was significant enough to act against and overcome the urging force of spring 10 thereby causing film cartridge 4 to move toward lower spindle 9. Accordingly, because film cartridge 4 moved, so too did film strip F. Because dimension d2 is larger than dimension d1, film cartridge 4 was allowed to move a distance equal to dimension d2. As such, film strip F became damaged (e.g., creased, torn, etc.) at trauma point T because film strip F (and, in particular, bottom portion Fu) was forced to come into contact with a guide rail system and film advancement channel defined, in part, by lower guide rail 25.
Additionally, the aforementioned problems associated with vertical movement of a film strip may be exacerbated by the fact that spindle 9 can also rock or tilt as a result of having a relatively large distance over which to move (i.e., a distance equal to dimension d2). If spindle 9 rocks or tilts, film cartridge 4 and film strip F can correspondingly move within film cartridge compartment 3 thereby increasing the likelihood of damage to film strip F.
Accordingly, there exists a need for new and improved systems for preventing damage to film strips that retractably extend from film cartridges. Without such new and improved systems, camera users will continue to run the risk of having their pictures destroyed due to film strip damage that may result from camera movement.